呼气相胸片的识别研究

根据呼气相胸片中肺部区域灰度较高的特点，通过边缘提取和边缘跟踪确定胸部区域，运用最大类间方差方法确定图像分割的阈值．再提取出肺部区域，然后求出肺部的灰度均值。但这样的结果并不理想。于是在此基础上提出修正方案，即以肺部灰度均值和骨骼灰度均值的比值作为特征值．即比例法。此方法可以较客观的识别呼气相胸片。最后用类间距离对这两种方法进行了量化比较。     

Thymocyte and peripheral blood T lymphocyte subpopulation changes in piglets following in utero infection with porcine reproductive and respiratory syndrome virus

Piglets infected in utero with porcine reproductive and respiratory syndrome virus (PRRSV) are born severely immunocompromised. In this article we more closely examine the effects of in utero PRRSV infection on circulating and thymic T cell populations. Numbers of CD4+, CD8+, and dual-positive lymphocytes were quantitated in circulation and in the thymus during the 2 weeks following birth. At birth we found that the number of circulating lymphocytes was suppressed by 60%. Lymphocyte numbers were also suppressed by 42% at day 7, but by day 14 the number of lymphocytes had rebounded and was actually 47% greater than controls. At birth and day 7, a drop in the number of CD4+ cells could partially explain the suppression we observed, while the rebound in total lymphocyte numbers seen at day 14 was due to a nearly fourfold increase in the number of circulating CD8+ cells. As a result, the normal CD4+:CD8+ ratio of between 1.4 and 2.2 for neonatal pigs was reduced to 0.1-0.5. The thymuses of infected piglets were found to be 50% smaller than those of control pigs and were characterized by cortical involution and severe cortical depletion of thymocytes. Analysis of the population of thymocytes revealed that double-positive thymocytes were suppressed to a greater degree than either single positive subpopulation. In addition, we show that the number of thymocytes undergoing apoptosis was increased twofold in piglets infected with PRRSV. Taken together, these results help explain the dramatic immunosuppression observed in neonatal animals infected in utero with PRRSV.     

金针菇子实体多糖提取物对人肝癌SMMC—7721细胞的抑增殖作用

金针菇子实体经热水提取，乙醇沉淀，胰蛋白酶水解，Ｓｅｖａｇ法去除蛋白质，乙醇分级沉淀等处理得金针菇子实体多糖。研究了该多糖对人肝部ＳＭＭＣ－７７２１细胞生长曲线，有丝分裂指数及线粒体活性的影响。结果表明该多糖对体外培养的人肝癌ＳＭＭＣ－７７２１细胞具一定抑制作用。     

大鼠脑皮质微血管内皮细胞培养和形态学观察

为获取较纯净脑微血管内皮细胞进行血脑屏障的病理生理研究，我们采用脑组织匀浆、过滤和酶消化技术分离大鼠脑微血管，对分离的脑微血管内皮细胞进行了体外培养和形态学观察。倒置显微镜下，细胞具有单层“卵石样”排列的典型特征、电镜观察可见细胞间连接，免疫酶技术显示，95％以上的细胞为第Ⅷ因子相关抗原反应阳性，进一步证实为血管内皮细胞。     

47例骨髓穿刺干抽的临床和病理分析

分析４７例骨髓穿刺干抽的临床和病理改变，干抽占同期１３１９例骨穿的３．６％。根据骨髓细胞的密度和间质纤维增殖的程度，把干抽的原因分为４类：高细胞伴间质细胞增多者１９例（４２．２％）；间质细胞增多者１４例（３１．１％）；高细胞者８例（１７．８％）及低细胞者４例（８．９％）。主要疾病为：急性淋巴细胞白血病（２５．５％），急性非淋巴细胞白血病（１７．０％），慢性白血病（１４．９％），骨髓转移瘤（１０．６     

脚压测量用传感器

本文讨论了用于脚压测量的四类压力传感器，电阻式传感器、压电式传感器，光电式传感器，电容式传感器介绍了其结构、原理和特点，并分析了几种典型的测量接口电路。     

Molecular typing of the etiologic agent of human granulocytic ehrlichiosis

The p44 gene of the agent of human granulocytic ehrlichiosis (aoHGE) encodes a 44-kDa major outer surface protein. A technique was developed for the typing of the aoHGE based on the PCR amplification of the p44 gene followed by a multiple restriction digest with HindIII, EcoRV, and AspI to generate restriction fragment length polymorphism patterns. Twenty-four samples of the aoHGE were collected from geographically dispersed sites in the United States and included isolates from humans, equines, canines, small mammals, and ticks. Six granulocytic ehrlichiosis (GE) types were identified. The GE typing method is relatively simple to perform, is reproducible, and is able to differentiate among the various isolates of granulocytic ehrlichiae in the United States. These characteristics suggest that this GE typing method may be an important epizootiological and epidemiological tool.     

白三烯C_4对大鼠胃粘膜微循环的影响及其在急性胃粘膜损伤中的作用

探讨了静注白三烯C_4(0.1ng·100g~(-1))对胃粘膜微循环的影响及其在急性胃粘膜损伤中的作用。实验由Wistar系雄性大鼠,实验前禁食24hr,饮水不限。发现:1.胃粘膜表层毛细血管口径迅速变细,部分消失,集合细静脉口径亦变细;10分钟时集合细静脉明显淤血和出血。2.氢气清除法证明,胃粘膜血流量明显减少,注后第15分钟时由注前1.230±0.093(M±SE)降至0.521±0.079ml·min~(-1)·100g~(-1)(P<0.01)。3.反射光谱法证明,胃粘膜局部表层微循环血液量(△Er)和Hb氧饱和度(F),均有不同程度下降。4.静注白三烯C_4(0.1ng·100g~(-1))及盐酸灌胃(0.2N1ml)均未见明显胃粘膜损伤,两者并用则损伤明显加重。结果表明,外源性白三烯C_4可引起严重胃粘膜微循环障碍,是诱发溃疡形成的重要因素之一。     

Biochemical analyses of multiple fractions of PKR purified from Escherichia coli.

PKR is a cellular protein kinase activated by double-stranded RNA (dsRNA) that phosphorylates eukaryotic initiation factor alpha (eIF2alpha) and inhibits protein translation. Activation of PKR is accompanied by Ser/Thr autophosphorylation on multiple sites. Because PKR negatively regulates cell growth, overexpression and purification of PKR are difficult to achieve. Here, we describe overexpression and purification of recombinant PKR protein from Escherichia coli under native conditions at the milligram level. Affinity, ion exchange, and gel filtration chromatographies revealed multiple fractions of PKR with distinctive biochemical characteristics. During gel filtration, a small amount of PKR was found in a high molecular weight (>300 kDa) fraction that also contained endogenous bacterial RNA. The PKR in this fraction has a constitutive substrate phosphorylation activity. The majority of PKR is found in fractions of lower molecular weight and is free of RNA but is differentially phosphorylated as examined by isoelectric focusing electrophoresis and can be further separated by gradient anion exchange chromatography. PKR eluted with low salt has a lower level of basal autophosphorylation, and its kinase activity can be induced by dsRNA. With an increasing NaCl gradient, the purified PKR exhibits an increased level of autophosphorylation and constitutive kinase activity but reduced dsRNA inducibility. The highest salt eluent of PKR exhibits little dsRNA-induced activation. The inducible activation of high salt eluent PKR by dsRNA can be partially restored by treatment with protein phosphatase 1. The production of multiple fractions of PKR with different biochemical properties in E. coli suggests that the spectrum of PKR activity and regulation in mammalian cells is likely to be similarly complex.